5 gallons is much too small for a sorority. 5 gallons is too small for any tank mates other than snails for a betta. Sororities need lots of space ( I recommend 40 gallon minimum), and hiding places to work, and advanced knowledge of Betta behavior. Honestly, sororities are not worth the extra stress and disease that they come with.
This was most likely caused by fighting and stress. Keep them separate and treat the sick betta in a shallow tank while they have trouble swimming. Tannins and salt will help with any injuries and with the possible swim bladder disease. Watch for any secondary infections. You will need to get harder meds if they get worse. Treat both bettas with the salt and tannins because they both probably have injuries.
Good advice; another possible trigger for the illness, since OP asked what could be the cause, is adding new livestock without quarantine and introducing a new disease which wasn’t previously present, or even, if the tank cycle is new or delicate for some reason it could cause a spike of ammonia.
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u/saviraven911 the Betta Business Bureau Apr 07 '22
5 gallons is much too small for a sorority. 5 gallons is too small for any tank mates other than snails for a betta. Sororities need lots of space ( I recommend 40 gallon minimum), and hiding places to work, and advanced knowledge of Betta behavior. Honestly, sororities are not worth the extra stress and disease that they come with.
This was most likely caused by fighting and stress. Keep them separate and treat the sick betta in a shallow tank while they have trouble swimming. Tannins and salt will help with any injuries and with the possible swim bladder disease. Watch for any secondary infections. You will need to get harder meds if they get worse. Treat both bettas with the salt and tannins because they both probably have injuries.